I checked the traffic through a VPN and this seems to connect. I tried to contact my ISP but they did not seem to have enough technical information. Anyway, there seems to be a routing problem between the FTP server and my ISP.

Thank you @ShyPixie for including the traceroute, it tells a lot about the issue (I did take the liberty to format the message though, the line endings were missing from the pasted text it seems).

The traceroute with the VPN is what the traceroute should look like: a few steps inside the network of the internet provider, then a number of hops through an intermediate network (cogentco.com in this case) after which it ends up at the network of Wildcard, who own the datacenter where we host your websites. It fails after that because we block further traceroutes within our network, but these results show that you can reach our network.

The traceroute without the VPN shows that the connection hits your internet provider, but is completely blocked afterwards. That’s very clear proof that your internet provider is blocking the connection. Whether that’s a technical error or on purpose I can’t tell from here.

I would highly recommend to send these traceroutes to your internet provider as well, because it clearly tells them what’s going on and that it’s something they should fix.